WASHINGTON — Two years after the nuclear crisis in Japan, the top U.S. regulator says American
nuclear power plants are safer than ever, although not trouble-free. A watchdog group calls that
assessment overly rosy.

All but five of the nation’s 104 nuclear reactors were performing at acceptable safety levels at
the end of 2012, Macfarlane said, citing a recent NRC report. “You can’t engage that many reactors
and not have a few that are going to have difficulty,” she said.

But the watchdog group, the Union of Concerned Scientists, has issued a scathing report saying
nearly 1 in 6 U.S. nuclear reactors experienced safety breaches last year, due in part to weak
oversight. The group accused the NRC of “tolerating the intolerable.”

Using the agency’s own data, the scientists group said 14 serious incidents, ranging from broken
or impaired safety equipment to a cooling-water leak, were reported last year. Over the past three
years, 40 of the 104 U.S. reactors experienced one or more serious safety-related incidents that
required additional action by the NRC, the report said.

“The NRC has repeatedly failed to enforce essential safety regulations,” wrote David Lochbaum,
director of the group’s Nuclear Safety Project and author of the study. “Failing to enforce
existing safety regulations is literally a gamble that places lives at stake.”

NRC officials disputed the report and said none of the reported incidents harmed workers or the
public.

Today marks the two-year anniversary of the 2011 earthquake and tsunami that crippled Japan’s
Fukushima Daiichi nuclear plant. U.S. regulators, safety advocates and the industry are now
debating whether safety changes imposed after the disaster have made the nation’s 65 nuclear plants
safer.

New rules imposed by the NRC require plant operators to install or improve venting systems to
limit core damage in a serious accident and set up sophisticated equipment to monitor water levels
in pools of spent nuclear fuel.

The plants also must improve protection of safety equipment installed after the Sept. 11, 2001,
terrorist attack and make sure they can handle damage to multiple reactors at the same time.

Macfarlane, who took over as NRC chairwoman in July, said U.S. plants are operating safely and
are making progress on the new rules, which impose a deadline for completion of 2016 — five years
after the Fukushima disaster. “So far, industry seems to be cooperating,” she said.

The NRC has been working closely with plant operators “to make sure they understand what we are
requiring and that we understand about their situation as well,” Macfarlane said.

Even so, the U.S. industry faces a range of difficulties. Problem-plagued plants in Florida and
Wisconsin are slated to close, and four other reactors remain offline because of safety concerns.
Offline reactors include two at the beleaguered San Onofre nuclear power plant in southern
California, which hasn’t produced electricity since January 2012, when a tiny radiation leak led to
the discovery of damage to hundreds of tubes that carry radioactive water.

Joseph Pollock, vice president of Nuclear Energy Institute, an industry trade association, said
plant operators are “working aggressively” to meet the 2016 timeline set by the NRC and already
have spent upward of $40 million on safety efforts. Utilities have bought more than 1,500 pieces of
equipment, from emergency diesel generators to sump pumps and satellite phones, Pollock said, and
the industry is setting up two regional response centers in Memphis, Tenn., and Phoenix.

The industry expects to meet the 2016 timeline “with the current understood requirements,”
Pollock said. If the requirements change or new regulations are added, “then, obviously, we would
have to review that,” he said.

Even before the new rules are completely in place, the NRC is considering a new regulation
related to the Japan disaster: requiring nuclear operators to spend tens of millions of dollars to
install filtered vents at two dozen reactors.

NRC staff recommended the filters as a way to prevent radioactive particles from escaping into
the atmosphere after a core meltdown. The filters are required in Japan and throughout much of
Europe, but U.S. utilities say they are unnecessary and expensive.

The filter issue has ignited a debate on Capitol Hill. Lawmakers from both parties have sent out
a flurry of dueling letters for and against the proposal. Twenty-eight Republicans in the House and
Senate, joined by more than two dozen House Democrats, have sent letters opposing the requirement
as hasty and unnecessary.

A dozen Democratic senators and five House members have written letters backing the requirement,
which they say will ensure public safety in the event of accident like Japan’s.